good morning to All
I apologize right away if I trivialize a complex topic in the hope of understanding something
If I understand correctly the dynamic behavior of a driver is expressed by its Qts which is a bit like the weight/power ratio of a car
Does a low Qts mean high acceleration and perhaps damping of the driver's diaphragm ?
My question is can the Qts give an indication of the response to an impulse of a driver?
I ask because finally i am able to measure TS parameters
I was thinking to use a wideband cheap driver but i measured a Qts close to 2
Better to put it aside ?
I apologize right away if I trivialize a complex topic in the hope of understanding something
If I understand correctly the dynamic behavior of a driver is expressed by its Qts which is a bit like the weight/power ratio of a car
Does a low Qts mean high acceleration and perhaps damping of the driver's diaphragm ?
My question is can the Qts give an indication of the response to an impulse of a driver?
I ask because finally i am able to measure TS parameters
I was thinking to use a wideband cheap driver but i measured a Qts close to 2
Better to put it aside ?
Qts has absolutely nothing to do with the diaphragm, damping, or any behavior of the driver EXCEPT AT RESONANCE (around Fs). Qts is just a parameter that is helpful for the characterization of the near resonance behavior of a driver. Do not make it anything more than it is.
With that said, the Q of the driver after it has been put into a box (the system Q) does indeed have a direct relationship with the main features in the time domain behavior (e.g. impulse response), but only the part due to the near resonance response. For example it says nothing about the little wiggles in the impulse response after the main peak and any more rapid oscillations. So Qts is of limited value in evaluating what the impulse response will look like overall. Keep in mind that you can get a very good idea of the time domain behavior of a driver just by looking at... the frequency response! So use THAT as a guide, not some parameter like Qts, Qes, etc. Qts is primarily used to choose the box size and box type (sealed, vented, etc.).
Regarding your specific driver with Qts=2, this has too small a magnet to be useful for decent hifi IF it will be used near its resonance but it might be OK if high-passed. Why? It turns out that the filter used in the loudspeaker will change the frequency response of the driver (that is the primary purpose of the crossover filter) and this also changes the overall time domain behavior. So if you use this Qts=2 driver with a highpass filter (e.g. like a midrange) that cuts out the low frequencies including the part with a couple of octaves of Fs, then the filter is also removing the bad time domain behavior of the high Qts driver. This fact seems to be lost on certain DIYers who strive for drivers with low Mms and low Qes, only to use them as a woofer in a loudspeaker with a lowpass filter than removes the high frequencies and therefore makes the driver in the time domain seem "slow" when a "fast" driver was their goal. Don't be that guy.
With that said, the Q of the driver after it has been put into a box (the system Q) does indeed have a direct relationship with the main features in the time domain behavior (e.g. impulse response), but only the part due to the near resonance response. For example it says nothing about the little wiggles in the impulse response after the main peak and any more rapid oscillations. So Qts is of limited value in evaluating what the impulse response will look like overall. Keep in mind that you can get a very good idea of the time domain behavior of a driver just by looking at... the frequency response! So use THAT as a guide, not some parameter like Qts, Qes, etc. Qts is primarily used to choose the box size and box type (sealed, vented, etc.).
Regarding your specific driver with Qts=2, this has too small a magnet to be useful for decent hifi IF it will be used near its resonance but it might be OK if high-passed. Why? It turns out that the filter used in the loudspeaker will change the frequency response of the driver (that is the primary purpose of the crossover filter) and this also changes the overall time domain behavior. So if you use this Qts=2 driver with a highpass filter (e.g. like a midrange) that cuts out the low frequencies including the part with a couple of octaves of Fs, then the filter is also removing the bad time domain behavior of the high Qts driver. This fact seems to be lost on certain DIYers who strive for drivers with low Mms and low Qes, only to use them as a woofer in a loudspeaker with a lowpass filter than removes the high frequencies and therefore makes the driver in the time domain seem "slow" when a "fast" driver was their goal. Don't be that guy.
Hi ! thank you for the very kind and precious advice
I cannot understand how i could predict the response to an impulse from the frequency response
i guess that a very clean CSD plot should be a must for any driver
Regarding the driver it is a 3" concave cone and has also a fs=200 Hz
and yes i was thinking to use it from 400Hz up in a 2 way with a 8" woofer used up to 400Hz
i cannot listen above 13k these days
I cannot understand how i could predict the response to an impulse from the frequency response
i guess that a very clean CSD plot should be a must for any driver
Regarding the driver it is a 3" concave cone and has also a fs=200 Hz
and yes i was thinking to use it from 400Hz up in a 2 way with a 8" woofer used up to 400Hz
i cannot listen above 13k these days
by the way these are the drivers
i like the way they sound But with a fs=200Hz they cannot provide any decent bass
But what above 400 Hz ?
i like the way they sound But with a fs=200Hz they cannot provide any decent bass
But what above 400 Hz ?
Thanks and I have to elaborate a bit on my question
The goal would be to reproduce with two ways the range from 50 to 14 kHz (i am old)
The normal woofer and tweeter solution provides a cut around 1.5-2kHz
to use even a 10" woofer (i like a robust bass) I will need a upper driver that can cover at least from 500Hz up
10" woofers do not work above 500Hz nicely
no tweeter can go down to 500 They usually have a fs of about 1kHz
and dome mids cannot go above 4-5kHz
so I'm thinking of using a small wideband driver
Unfortunately I don't have the tools to do the frequency response yet
only the Dayton Audio DATS and I'm measuring the fs of what could go and I have on hand
a suitable fs for the upper drover should be around 200 or 300Hz like the Edifier driver
i know it is a pc speaker driver
but once cut in the lows who knows ?
i like the way it sounds a lot
The goal would be to reproduce with two ways the range from 50 to 14 kHz (i am old)
The normal woofer and tweeter solution provides a cut around 1.5-2kHz
to use even a 10" woofer (i like a robust bass) I will need a upper driver that can cover at least from 500Hz up
10" woofers do not work above 500Hz nicely
no tweeter can go down to 500 They usually have a fs of about 1kHz
and dome mids cannot go above 4-5kHz
so I'm thinking of using a small wideband driver
Unfortunately I don't have the tools to do the frequency response yet
only the Dayton Audio DATS and I'm measuring the fs of what could go and I have on hand
a suitable fs for the upper drover should be around 200 or 300Hz like the Edifier driver
i know it is a pc speaker driver
but once cut in the lows who knows ?
i like the way it sounds a lot
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To develop your own multi way speaker you need to know driver freq. and impedance response, Qtc, Vas and fs. If you don't know these, or can't measure them, there's no use to try and design your own speaker. Build some proven design.
Thank you very much for your valuable advice
I can measure free air parameters now Next step will be the purchase of a cheap calibrated microphone for measure frequency response
The woofer will have its own separate enclosure and it will be close This should simplify the project
and also the more the ways the more the complexity
Someone say that 4 ways are needed to cover the audio range with conventional cones and domes (but there is no consensus)
so 2 ways will be a though compromise i am afraid I have to renounce to lowest basses and highest highs
I can measure free air parameters now Next step will be the purchase of a cheap calibrated microphone for measure frequency response
The woofer will have its own separate enclosure and it will be close This should simplify the project
and also the more the ways the more the complexity
Someone say that 4 ways are needed to cover the audio range with conventional cones and domes (but there is no consensus)
so 2 ways will be a though compromise i am afraid I have to renounce to lowest basses and highest highs
To design a loudspeaker with a passive crossover you need to know two things:
1. The frequency response of each driver, when mounted in the loudspeaker enclosure and
2. The impedance response of each driver, when mounted in the loudspeaker enclosure.
When you have those two pieces of information for each driver, you can use software to design a very good crossover and have a nice sounding loudspeaker.
It's great that you will be buying a calibrated microphone. Depending on which one you purchase you may also need an audio interface with a microphone preamp. You also need a computer and software to perform the frequency response measurements, but the software can be obtained for free (ARTA, or RoomEQWizard a.k.a. REW). Crossover design software is also free: see VituixCAD, for example.
One challenge is to make acoustic measurements properly, so that you are measuring only the loudspeaker and not the room plus the loudspeaker. But that topic can wait until later!
1. The frequency response of each driver, when mounted in the loudspeaker enclosure and
2. The impedance response of each driver, when mounted in the loudspeaker enclosure.
When you have those two pieces of information for each driver, you can use software to design a very good crossover and have a nice sounding loudspeaker.
It's great that you will be buying a calibrated microphone. Depending on which one you purchase you may also need an audio interface with a microphone preamp. You also need a computer and software to perform the frequency response measurements, but the software can be obtained for free (ARTA, or RoomEQWizard a.k.a. REW). Crossover design software is also free: see VituixCAD, for example.
One challenge is to make acoustic measurements properly, so that you are measuring only the loudspeaker and not the room plus the loudspeaker. But that topic can wait until later!
Thank you very much I have a path to follow now
as i said i would like to dedicate a cabinet just to the woofer The woofer should cover the range up to about 500Hz
the remaining part of the range will be open for different solutions
My ideal speaker is a sat above a bass box That is my final solution
thanks a lot again
as i said i would like to dedicate a cabinet just to the woofer The woofer should cover the range up to about 500Hz
the remaining part of the range will be open for different solutions
My ideal speaker is a sat above a bass box That is my final solution
thanks a lot again
A little very quick explanation of the rationale behind the decision to keep the woofer physically separated and so mechanically decoupled from the mids-highs speaker cabinet
In a thread about cabinet resonances i learned that the goal for woofer cabinets is high stiffness to move the resonance modes up in frequency i.e. above the woofer working range
For the mid-high speaker instead the goal is high mass to move the resonances below the speaker working range
For this reason single piece full range speakers look like wrong to me Without even considering what moving a big size and very heavy speaker means Ok you move it once and not every day
Two pieces are better than one And also so much more flexible I love the solution a lot
end of ramblings Please excuse me
In a thread about cabinet resonances i learned that the goal for woofer cabinets is high stiffness to move the resonance modes up in frequency i.e. above the woofer working range
For the mid-high speaker instead the goal is high mass to move the resonances below the speaker working range
For this reason single piece full range speakers look like wrong to me Without even considering what moving a big size and very heavy speaker means Ok you move it once and not every day
Two pieces are better than one And also so much more flexible I love the solution a lot
end of ramblings Please excuse me